Max. bore on KB sleeves ?

Hi, what is the max. bore on KB sleeves in a KB stageVII water block for a blown engine. ( 14/71 HH, around 25 psi, fuel heads, 10.8:1 com., 4.375 stroke, ET-Bracket, max 8000 rpm) Can i go with a 4.375 bore ? OD of the sleeves is 4.7".

Thankx ITA

 

KB Sleeve Max Bore

I run the KB stage 7 water block also in a 526ci 10:1 compression, 40 psi boost, 8500 rpm. My sleeve OD is 4.635 if I measured that correctly. My sleeve bore/piston size is 4.375. That leaves the sleeve wall thickness at .130. I have not had any problems with the sleeves at this bore. 4.635OD - 4.375ID = .260 / 2 = .130 wall
If your sleeves are 4.700 then you should have .1625 wall thickness. It should be fine. There may be other opinions that differ from mine but that is my 2 cents worth.
Good luck,
Barry

 

I believe the max bore that KB recommends on a water sleeve is 4.310.

Call KB and ask. 562 869-1518.

 

Max Bore KB Sleeves

About how far to safely bore a KB sleeve, I found my notes where I talked to Ken Black in October of 2009. He told me over the phone at that time that a sleeve having a 4.635 od made of ductile iron material, that as long as the "step" in the sleeve was lower than the ring pack AND if the application was for blown alcohol, then 4.375 would work fine. Now, all that being said, if NITRO was the fuel used, he would NOT recommend it. A difference in cylinder pressure I assume. Whatever it is, 4.375 works for me. Another .02 worth.

 

I had 4.50 in my keith black water block

 

Max KB Sleeve Bore

I guess I am not alone in this overbore size idea. What is your sleeve od? What is your application? Blown alcohol, blown fuel, naturally aspirated something? Thanks

 

it was a few yrs back I don't remember od bore size but it was set up by a engine builder like that. It was a blown alcohol hemi making 25 lbs 7500 rpms motor speed never a problem.

 

Thanks everybody for help!!!